Attendant to a rise in the standard of living is an increasing diversification of consumer's taste. In the area of paints used for interior and exterior painting of homes and buildings, a noticeable trend is a shift in the consumer's interest away from the conventional single-colored decor in favor of paint products that are capable of producing multi-color effects in two or more colors.
The authors of the present invention previously disclosed two patent applications designed to provide paints that were capable of producing detailed, multi-color patterns with vivid clarity, in the publications "Method for the Manufacture of Multi-Color Pattern Finish Paint Constituents," Japanese OFFICIAL GAZETTE FOR PATENT PUBLICATIONS S63-145378; and "Method for the Manufacture of Colored Polymer Powder, and Molding Methods and Paints Using the Colored Polymer Powder," Japanese OFFICIAL GAZETTE FOR PATENT PUBLICATIONS H2-41371.
The disclosed technology involved mixing the following: a mixture of colored pigments and an emulsion resin, and particles of a vinyl chloride-based synthetic resin with or without a plasticizer; adding a metal salt to the mixture; and coating the surfaces of said vinyl chloride-based synthetic resin particles with a colored paint by means of salting out. The results were colored polymer powder particles with an average grain size of 10-200 .mu.m, and a paint that contained the colored polymer powder particles as an essential ingredient.
The technology that was disclosed by the inventors of the present invention involved a paint offering an excellent decorative property, and distinct from conventional mono-colored paints. That technology was capable of producing, by paint coating, a fine, detailed, multi-color, and marble-like texture, and offered a manufacturing method capable of producing such a paint. However, the disclosed technology was incapable of producing colored particles with an average grain size of 10-200 .mu.m, for producing such a marble-like effect, in high yields. Therefore, the disclosed technology contained yield problems.
Moreover, if resin particles other than vinyl chloride-based resin containing a plasticizer as the core material for the colored particles were used, the colored particles could not adequately coat the surface of the particles. Therefore, the previous technology was inadequate for use as an industrial-scale manufacturing method.
In the meantime, problems such as global warming due to a buildup of carbon dioxide and environmental issues such as the depletion of the ozone layer have become increasingly important.
Against this background, the development of industrial technologies that are capable of contributing to the protection of the global environment has become a pressing worldwide issue. However, paints in which an organic synthetic resin is used as a core substance, as noted above, suffer from the problem of combustion of the paint coating in an event of a fire. This produces carbon dioxide and can worsen the problems of global warming, ozone layer destruction, and acid rain. The net result is an inability to contribute to the protection of the global environment.